从cmake为QT5生成的MOC文件中存在错误

Question

我使用以下命令为QT5生成了moc文件

set (CMAKE_AUTOMOC ON)
set(CMAKE_INCLUDE_CURRENT_DIR ON)

然后我使用以下命令将moc文件添加到SRC中

SET(SRC
  src/main.cpp
  src/video_widget_surface.cpp
  src/video_widget.cpp
  src/video_player.cpp
#moc files
  moc/moc_video_player.cpp
  moc/moc_video_widget.cpp
  moc/moc_video_widget_surface.cpp

最后，我使用以下命令添加可执行文件

add_executable(somegui ${SRC})

但是我在moc文件中得到的错误是：

/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:54:6: error: 'VideoWidget' has not been declared
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:62:19: error: 'VideoWidget' has not been declared
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:68:20: error: 'VideoWidget' has not been declared
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:68:46: error: non-member function 'const QMetaObject* metaObject()' cannot have cv-qualifier
/other/Qt5.0.1/5.0.1/gcc_64/include/QtCore/qobject.h: In function 'const QMetaObject* metaObject()':
/other/Qt5.0.1/5.0.1/gcc_64/include/QtCore/qobject.h:401:33: error: 'QScopedPointer<QObjectData> QObject::d_ptr' is protected
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:70:21: error: within this context
/other/Qt5.0.1/5.0.1/gcc_64/include/QtCore/qobject.h:401:33: error: invalid use of non-static data member 'QObject::d_ptr'
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:70:21: error: from this location
/other/Qt5.0.1/5.0.1/gcc_64/include/QtCore/qobject.h:401:33: error: 'QScopedPointer<QObjectData> QObject::d_ptr' is protected
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:70:50: error: within this context
/other/Qt5.0.1/5.0.1/gcc_64/include/QtCore/qobject.h:401:33: error: invalid use of non-static data member 'QObject::d_ptr'
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:70:50: error: from this location
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp: At global scope:
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:73:7: error: 'VideoWidget' has not been declared
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp: In function 'void* qt_metacast(const char*)':
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:47: error: expected type-specifier before 'VideoWidget'
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:47: error: expected '>' before 'VideoWidget'
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:47: error: expected '(' before 'VideoWidget'
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:47: error: 'VideoWidget' was not declared in this scope
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:59: error: expected primary-expression before '>' token
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:61: error: invalid use of 'this' in non-member function
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:77:67: error: expected ')' before ';' token
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:78:40: error: cannot call member function 'virtual void* QWidget::qt_metacast(const char*)' without object
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp: At global scope:
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:81:5: error: 'VideoWidget' has not been declared
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp: In function 'int qt_metacall(QMetaObject::Call, int, void**)':
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:83:43: error: cannot call member function 'virtual int QWidget::qt_metacall(QMetaObject::Call, int, void**)' without object
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp: In function 'void* qt_metacast(const char*)':
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:79:1: warning: control reaches end of non-void function [-Wreturn-type]
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp: In function 'const QMetaObject* metaObject()':
/other/workspace/perception/somestuff/moc/moc_video_widget.cpp:71:1: warning: control reaches end of non-void function [-Wreturn-type]
make[2]: *** [CMakeFiles/somestuff.dir/moc/moc_video_widget.cpp.o] Error 1
make[1]: *** [CMakeFiles/somestuff.dir/all] Error 2
make: *** [all] Error 2

我的理解是在创建的moc文件中有一些错误。但我无法控制它是如何创建的。现在我该如何解决这个bug呢？

Answer 1

CMake文档并没有那么糟糕，请不要忽视阅读它。您误解了的概念

AUTOMOC是一个布尔值，指定CMake是否会自动处理Qt moc预处理器，即不必使用QT4_WRAP_CPP()宏。目前支持Qt4。当此属性设置为TRUE时，CMake将在构建时扫描源文件并相应地调用moc。如果找到像#include "moc_foo.cpp"这样的#include语句，Q_OBJECT类声明应该出现在头文件中，并在头文件上运行moc。如果找到类似#include "foo.moc"的#include语句，则在当前源文件中应包含Q_OBJECT，并在文件本身上运行moc。此外，还会解析所有头文件中的Q_OBJECT宏，如果找到，还会对这些文件执行moc。

因此，首先，您不应该显式地将生成的moc文件添加到源代码中，并将它们推入可执行编译。换句话说，你只推送你的来源：

SET(SRC
  src/main.cpp
  src/video_widget_surface.cpp
  src/video_widget.cpp
  src/video_player.cpp)

而moc是由CMake自动处理的。

其次，正如文档中所述：

• 如果Q_OBJECT在foo.h中(即在头文件中声明了QObject )，则在相应的foo.cpp中不要忘记添加#include "moc_foo.cpp"，最好在文件的末尾添加；
• 如果<代码>D31在<代码>D32中(即在源文件中声明了<代码>D33)，那么在<代码>D34本身不要忘记添加，最好在文件的末尾添加。H236F237